Image sensors and electronic devices including the same

ABSTRACT

Image sensors, and electronic devices including the image sensors, include a first photoelectronic device including at least one of a blue photoelectronic device sensing light in a blue wavelength region, a red photoelectronic device sensing light in a red wavelength region, and a green photoelectronic device sensing light in a green wavelength region, and a second photoelectronic device stacked on one side of the first photoelectronic device without being interposed by a color filter, wherein the second photoelectronic device senses light in an infrared region.

RELATED APPLICATIONS

This application claims priority, under 35 U.S.C. §119, to and thebenefit of Korean Patent Application No. 10-2014-0099084 filed in theKorean Intellectual Property Office on Aug. 1, 2014, the entire contentsof which are incorporated herein by reference.

BACKGROUND

Field

Image sensors and electronic devices including the same are disclosed.

Description of the Related Art

A photoelectronic device converts light into an electrical signal usingphotoelectronic effects. The photoelectronic device may include aphotodiode, a phototransistor, and the like. The photoelectronic devicemay be applied to an image sensor, a solar cell, and the like.

An image sensor including a photodiode requires a small size and/or highresolution. In order to manufacture an image sensor having a smallersize, a size of a pixel needs to become smaller. However, sensitivitymay be deteriorated because an absorption area becomes smaller due tosmall pixels. In addition, luminance may deteriorate because of lowillumination.

SUMMARY

According to example embodiments, image sensors are disclosed.

Other example embodiments provide image sensors that realize down-sizingand high sensitivity and high luminescence characteristics under lowillumination.

Further example embodiments provide electronic devices including theimage sensors.

According to some example embodiments, an image sensor includes a firstphotoelectronic device including at least one of a blue photoelectronicdevice sensing light in a blue wavelength region, a red photoelectronicdevice sensing light in a red wavelength region, and a greenphotoelectronic device sensing light in a green wavelength region, and asecond photoelectronic device stacked on one side of the firstphotoelectronic device without being interposed by a color filter,wherein the second photoelectronic device senses light in an infraredregion.

The blue wavelength region may have a maximum absorption wavelength(λ_(max)) at greater than, or equal to, about 400 nm and less than 500nm, the red wavelength region may have a maximum absorption wavelength(λ_(max)) at greater than about 580 nm, and less than, or equal to,about 700 nm, the green wavelength region may have a maximum absorptionwavelength (λ_(max)) at about 500 nm to about 580 nm, and the infraredregion may have a maximum absorption wavelength (λ_(max)) at greaterthan about 700 nm.

The first photoelectronic device may include the blue photoelectronicdevice, the red photoelectronic device, and the green photoelectronicdevice, and the blue photoelectronic device, the red photoelectronicdevice, and the green photoelectronic device may be integrated in asilicon substrate.

The image sensor may further include a color filter layer on the oneside of the first photoelectronic device or one side of the secondphotoelectronic device, wherein the color filter layer includes a bluefilter selectively absorbing light in a blue wavelength region, a redfilter selectively absorbing light in a red wavelength region, and agreen filter selectively absorbing light in a green wavelength region.

The color filter layer may be at a side of the image sensor on whichlight is incident.

The first photoelectronic device may include an organic photoelectronicdevice, and the organic photoelectronic device may include a pair oflight-transmitting electrodes facing each other and a visible lightabsorption layer interposed between the pair of light-transmittingelectrodes. The visible light absorption layer may selectively absorblight in one of the blue wavelength region, the red wavelength region,and the green wavelength region.

The visible light absorption layer may selectively absorb light in agreen wavelength region.

The image sensor may further include a silicon substrate on one side ofthe organic photoelectronic device, wherein the blue photoelectronicdevice and the red photoelectronic device may be integrated in thesilicon substrate.

The blue photoelectronic device and the red photoelectronic device maybe spaced apart from each other in a horizontal direction.

The image sensor may further include a color filter layer between theorganic photoelectronic device and the silicon substrate, wherein thecolor filter layer includes a blue filter selectively absorbing light ina blue wavelength region and a red filter selectively absorbing light ina red wavelength region.

The blue photoelectronic device and the red photoelectronic device maybe stacked in a vertical direction, and the red photoelectronic devicemay be positioned further from a surface of the silicon substrate thanthe blue photoelectronic device.

The second photoelectronic device may include a pair oflight-transmitting electrodes facing each other, and an infrared lightabsorption layer interposed between the pair of light-transmittingelectrodes. The infrared light absorption layer may selectively absorblight in an infrared region.

The infrared light absorption layer may include at least one selectedfrom a quinoid metal complex compound, a cyanine compound, an immoniumcompound, a diimmonium compound, a triarylmethane compound, adipyrromethene compound, diquinone compound, a naphthoquinone compound,an anthraquinone compound, a squarylium compound, a rylene compound, aphthalocyanine compound, a naphthalocyanine compound, a perylenecompound, an anthraquinone compound, a nickel-dithiol complex compound,and a derivative thereof.

The first photoelectronic device and the second photoelectronic devicemay contact each other, or a transparent insulator may be interposedbetween the first photoelectric device and the second photoelectronicdevice.

According to further example embodiments, an electronic device includingthe image sensor is provided.

The electronic device may be a mobile phone, a digital camera, or abio-sensing camera.

BRIEF DESCRIPTION OF THE DRAWINGS

Example embodiments will be more clearly understood from the followingdetailed description taken in conjunction with the accompanyingdrawings. FIGS. 1-3 represent non-limiting, example embodiments asdescribed herein.

FIG. 1 is a cross-sectional view of an image sensor according someexample embodiments,

FIG. 2 is a cross-sectional view of an image sensor according to otherexample embodiments, and

FIG. 3 is a cross-sectional view of an image sensor according to furtherexample embodiments.

FIG. 4 is a cross-sectional view of an image sensor according to furtherexample embodiments.

DETAILED DESCRIPTION

Various example embodiments will now be described more fully withreference to the accompanying drawings in which some example embodimentsare shown. However, specific structural and functional details disclosedherein are merely representative for purposes of describing exampleembodiments. Thus, the invention may be embodied in many alternate formsand should not be construed as limited to only example embodiments setforth herein. Therefore, it should be understood that there is no intentto limit example embodiments to the particular forms disclosed, but onthe contrary, example embodiments are to cover all modifications,equivalents, and alternatives falling within the scope.

In the drawings, the thicknesses of layers and regions may beexaggerated for clarity, and like numbers refer to like elementsthroughout the description of the figures.

Although the terms first, second, etc. may be used herein to describevarious elements, these elements should not be limited by these terms.These terms are only used to distinguish one element from another. Forexample, a first element could be termed a second element, and,similarly, a second element could be termed a first element, withoutdeparting from the scope of example embodiments. As used herein, theterm “and/or” includes any and all combinations of one or more of theassociated listed items.

It will be understood that, if an element is referred to as being“connected” or “coupled” to another element, it can be directlyconnected, or coupled, to the other element or intervening elements maybe present. In contrast, if an element is referred to as being “directlyconnected” or “directly coupled” to another element, there are nointervening elements present. Other words used to describe therelationship between elements should be interpreted in a like fashion(e.g., “between” versus “directly between,” “adjacent” versus “directlyadjacent,” etc.).

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of exampleembodiments. As used herein, the singular forms “a,” “an” and “the” areintended to include the plural forms as well, unless the context clearlyindicates otherwise. It will be further understood that the terms“comprises,” “comprising,” “includes” and/or “including,” if usedherein, specify the presence of stated features, integers, steps,operations, elements and/or components, but do not preclude the presenceor addition of one or more other features, integers, steps, operations,elements, components and/or groups thereof.

Spatially relative terms (e.g., “beneath,” “below,” “lower,” “above,”“upper” and the like) may be used herein for ease of description todescribe one element or a relationship between a feature and anotherelement or feature as illustrated in the figures. It will be understoodthat the spatially relative terms are intended to encompass differentorientations of the device in use or operation in addition to theorientation depicted in the figures. For example, if the device in thefigures is turned over, elements described as “below” or “beneath” otherelements or features would then be oriented “above” the other elementsor features. Thus, for example, the term “below” can encompass both anorientation that is above, as well as, below. The device may beotherwise oriented (rotated 90 degrees or viewed or referenced at otherorientations) and the spatially relative descriptors used herein shouldbe interpreted accordingly.

Example embodiments are described herein with reference tocross-sectional illustrations that are schematic illustrations ofidealized embodiments (and intermediate structures). As such, variationsfrom the shapes of the illustrations as a result, for example, ofmanufacturing techniques and/or tolerances, may be expected. Thus,example embodiments should not be construed as limited to the particularshapes of regions illustrated herein but may include deviations inshapes that result, for example, from manufacturing. For example, animplanted region illustrated as a rectangle may have rounded or curvedfeatures and/or a gradient (e.g., of implant concentration) at its edgesrather than an abrupt change from an implanted region to a non-implantedregion. Likewise, a buried region formed by implantation may result insome implantation in the region between the buried region and thesurface through which the implantation may take place. Thus, the regionsillustrated in the figures are schematic in nature and their shapes donot necessarily illustrate the actual shape of a region of a device anddo not limit the scope.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which example embodiments belong. Itwill be further understood that terms, such as those defined in commonlyused dictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art andwill not be interpreted in an idealized or overly formal sense unlessexpressly so defined herein.

In order to more specifically describe example embodiments, variousfeatures will be described in detail with reference to the attacheddrawings. However, example embodiments described are not limitedthereto.

Hereinafter, an image sensor according to example embodiments isdescribed. Herein, a CMOS image sensor as an example of an image sensoris described. However, example embodiments are not limited thereto.

An image sensor according to some example embodiments includes a firstphotoelectronic device sensing light in a visible light region and asecond photoelectronic device sensing light in an infrared region.

The first photoelectronic device may sense light in a visible lightregion, and may include at least one of a blue photoelectronic devicesensing light in a blue wavelength region, a red photoelectronic devicesensing light in a red wavelength region, and a green photoelectronicdevice sensing light in a green wavelength region. Herein, the bluewavelength region may have a maximum absorption wavelength (λ_(max)) atgreater than, or equal to, about 400 nm and less than 500 nm, the redwavelength region may have a maximum absorption wavelength (λ_(max)) atgreater than about 580 nm and less than or equal to about 700 nm, andthe green wavelength region may have a maximum absorption wavelength(λ_(max)) at about 500 nm to about 580 nm.

The second photoelectronic device may sense light in an infrared region,wherein the infrared region may include, for example, a near-infraredray region, a mid-infrared region, and a far-infrared region. Forexample, the infrared region may have a maximum absorption wavelength(λ_(max)) at greater than about 700 nm. The infrared region may have,for example, a maximum absorption wavelength (λ_(max)) of greater thanabout 700 nm and less than or equal to about 3 μm.

The first photoelectronic device and the second photoelectronic devicemay be stacked, and the first photoelectronic device may be positionedat a light incidence side or the second photoelectronic device may bepositioned at a light incidence side. The first photoelectronic deviceand the second photoelectronic device may contact each other, or may beinterposed by a transparent insulator. The first photoelectronic deviceand the second photoelectronic device are not interposed by a colorfilter.

FIG. 1 is a cross-sectional view of an image sensor according to someexample embodiments.

Referring to FIG. 1, an image sensor according to some exampleembodiments include a semiconductor substrate 110 integrated with afirst photoelectronic device including a blue photoelectronic device50B, a red photoelectronic device 50R, and a green photoelectronicdevice 50G, a lower insulation layer 60, a second photoelectronic device90, and a color filter layer 70.

The semiconductor substrate 110 may be a silicon substrate, and isintegrated with the blue photoelectronic device 50B, the redphotoelectronic device 50R, the green photoelectronic device 50G, chargestorage units 55I, and transmission transistors (not shown). The bluephotoelectronic device 50B, the red photoelectronic device 50R, and thegreen photoelectronic device 50G may be photodiodes. The bluephotoelectronic device 50B and a first transmission transistor may beintegrated in each blue pixel, the red photoelectronic device 50R and asecond transmission transistor may be integrated in each red pixel, andthe green photoelectronic device 50G and a third transmission transistormay be integrated in each green pixel. The charge storage units 55I areelectrically connected to the second photoelectronic device 90.

A metal wire (not shown) and a pad (not shown) are formed on thesemiconductor substrate 110. In order to decrease signal delay, themetal wire and pad may be made of a metal having low resistivity, forexample, aluminum (Al), copper (Cu), silver (Ag), and alloys thereof,but is not limited thereto. However, example embodiments are not limitedto the structure, and the metal wire and pad may be positioned under theblue photoelectronic device 50B, the red photoelectronic device 50R, andthe green photoelectronic device 50G.

The lower insulation layer 60 is formed on the semiconductor substrate110. The lower insulation layer 60 may be made of an inorganicinsulating material such as a silicon oxide and/or a silicon nitride, ora low dielectric constant (low K) material such as SiC, SiCOH, SiCO, andSiOF.

The lower insulation layer 60 has a trench exposing the photoelectronicdevices 50B, 50R, and 50G and the charge storage unit 55I of each pixel.The trench may be filled with fillers. The lower insulation layer 60 maybe omitted.

The second photoelectronic device 90 is formed on the lower insulationlayer 60.

The second photoelectronic device 90 includes a lower electrode 91 andan upper electrode 92 facing each other, and an infrared lightabsorption layer 93 interposed between the lower electrode 91 and theupper electrode 92.

One of the lower electrode 91 and the upper electrode 92 is an anode andthe other is a cathode. The lower electrode 91 and the upper electrode92 may be light-transmitting electrodes. The light-transmittingelectrodes may be made of, for example, a transparent conductor such asindium tin oxide (ITO) or indium zinc oxide (IZO), or may be metal thinlayers having a thin thickness of several nanometers or several tens ofnanometers or metal thin layers having a thin thickness of severalnanometers to several tens of nanometers doped with a metal oxide.

The infrared light absorption layer 93 may include a materialselectively absorbing light in an infrared region. The infrared lightabsorption layer 93 may include a p-type and an n-type semiconductor. Atleast one of the p-type semiconductor and the n-type semiconductor maybe a material selectively absorbing light in an infrared region, forexample, a quinoid metal complex compound, a cyanine compound, animmonium compound, a diimmonium compound, a triarylmethane compound, adipyrromethene compound, a diquinone compound, a naphthoquinonecompound, an anthraquinone compound, a squarylium compound, a rylenecompound, a phthalocyanine compound, a naphthalocyanine compound, aperylene compound, an anthraquinone compound, a nickel-dithiol complexcompound, a derivative thereof, or a combination thereof, but exampleembodiments are not limited thereto.

The infrared light absorption layer 93 may have a thickness of about 1nm to about 500 nm. Within the range, the infrared light absorptionlayer 93 may have a thickness of about 5 nm to about 300 nm. When theinfrared light absorption layer 93 has a thickness within the range, theinfrared light absorption layer 93 may effectively absorb light in aninfrared region, effectively separate holes from electrons, and allowthe separated holes and electrons to migrate, effectively improvingphotoelectric conversion efficiency.

The second photoelectronic device 90 may produce excitons inside theimage sensor device when light enters from the upper electrode 92, andthe infrared light absorption layer 93 selectively absorbs light in theinfrared ray wavelength region. Excitons are separated into holes andelectrons in the infrared light absorption layer 93, and the separatedholes are moved to the anode side, which is one of the lower electrode91 and the upper electrode 92, and the separated electrons are moved toa cathode which is the other of the lower electrode 91 and the upperelectrode 92, so as to allow a current to flow. The separated electronsor holes may be collected in the charge storage units 55I.

The second photoelectronic device 90 selectively absorbs light in aninfrared region, and transmits light in other wavelength regions besidesthe infrared region.

The color filter layer 70 includes a blue filter 70B selectivelyabsorbing light in a blue wavelength region, a red filter 70Rselectively absorbing light in a red wavelength region, and a greenfilter 70G selectively absorbing light in a green wavelength region. Theblue filter 70B, the red filter 70R, and the green filter 70G may berespectively positioned in the blue pixel, the red pixel, and the greenpixel. The blue filter 70B absorbs light in a blue wavelength region andtransfers it to the blue photoelectronic device 50B, the red filter 70Rabsorbs light in a red wavelength region and transfers it to the redphotoelectronic device 50R, and the green filter 70G absorbs light in agreen wavelength region and transfers it to the green photoelectronicdevice 50G. The color filter layer 70 may transmit light in an infraredregion.

A focusing lens (not shown) may be further formed on the color filterlayer 70. The focusing lens may control a direction of incident lightand gather the light in one region. The focusing lens may have a shapeof, for example, a cylinder or a hemisphere, but is not limited thereto.

In FIG. 1, the second photoelectronic device 90 is stacked on thesemiconductor substrate 110, but example embodiments are not limitedthereto, and the semiconductor substrate 110 may be stacked on thesecond photoelectronic device 90.

As described above, the image sensor according to the present exampleembodiments includes the first photoelectronic device sensing light in avisible light region and the second photoelectronic device sensing lightin an infrared region that are stacked in a vertical direction, andthereby features of the first photoelectronic device and the secondphotoelectronic device may be maintained without increasing an area ofthe image sensor. Particularly, sensitivity and luminance of the imagesensor may be prevented from abruptly decreasing under low illuminationenvironments of, for example, less than about 11 lux, and highsensitivity and high luminescence characteristics may be realized due tothe second photoelectronic device sensing light in an infrared region.

The image sensor according to the present example embodiments includesthe color filter layer 70 positioned at the light incidence side, andthereby, a part of visible light may be absorbed and/or reflected by thelight-transmitting electrode of the second photoelectronic device 90 andthus visible light transmittance may be prevented from decreasing,compared with a structure where the second photoelectronic device 90 isdisposed on the color filter layer 70. Therefore, transmittance ofvisible light to the first photoelectronic device may be prevented fromdecreasing and efficiency caused thereby may be prevented fromdecreasing.

The image sensor according to the present example embodiments includesthe color filter layer 70 positioned at the light incidence side, andthereby, areas of the color filters 70B, 70R, and 70G for absorbinglight and an aperture ratio of each pixel increase and sensitivity isimproved, compared with a structure where the second photoelectronicdevice 90 is disposed on the color filter layer 70. When the secondphotoelectronic device 90 is disposed on the color filter layer 70, anaperture ratio of each pixel decreases and thus sensitivity may bedeteriorated by decreasing areas of the color filters 70B, 70R, and 70Gin order to form spaces of trenches connecting the secondphotoelectronic device 90 and the charge storage units 55I.

FIG. 2 is a cross-sectional view of an image sensor according to otherexample embodiments.

Referring to FIG. 2, an image sensor according to other exampleembodiments includes a semiconductor substrate 110 including a bluephotoelectronic device 50B and a red photoelectronic device 50R, a lowerinsulation layer 60, color filters 70B and 70R, an intermediateinsulation layer 65, an organic photoelectronic device 100, an upperinsulation layer 80, and a second photoelectronic device 90.

The semiconductor substrate 110 may be a silicon substrate, and isintegrated with the blue photoelectronic device 50B, the redphotoelectronic device 50R, charge storage units 55G, and transmissiontransistors (not shown). The blue photoelectronic device 50B and redphotoelectronic device 50R may be photodiodes. The blue photoelectronicdevice 50B and the red photoelectronic device 50R may be spaced apartfrom each other in a horizontal direction. The blue photoelectronicdevice 50B and the respective transmission transistor may be integratedin each blue pixel, the red photoelectronic device 50R and therespective transmission transistor may be integrated in each red pixel,and the respective charge storage unit 55G may be electrically connectedwith the organic photoelectronic device 100.

A metal wire (not shown) and a pad (not shown) are formed on thesemiconductor substrate 110. In order to decrease signal delay, themetal wire and pad may be made of a metal having low resistivity, forexample, aluminum (Al), copper (Cu), silver (Ag), and alloys thereof,but is not limited thereto. However, example embodiments are not limitedto the structure, and the metal wire and pad may be positioned under theblue photoelectronic device 50B and the red photoelectronic device 50R.

The lower insulation layer 60 is formed on the semiconductor substrate110. The lower insulation layer 60 may be made of an inorganicinsulating material such as a silicon oxide and/or a silicon nitride, ora low dielectric constant (low K) material such as SiC, SiCOH, SiCO, andSiOF.

The lower insulation layer 60 has a trench exposing the photoelectronicdevices 50B, 50R, and 50G and the charge storage unit 55G of each pixel.The trench may be filled with fillers.

The color filter layers 70B and 70R are formed on the lower insulationlayer 60. The color filter layers 70B and 70R include the blue filter70B formed in the blue pixel and the red filter 70R filled in the redpixel. The color filter 70B of the blue pixel absorbs light in a bluewavelength region and transfers it to the blue photoelectronic device50B, and the color filter 70R of the red pixel absorbs light in a redwavelength region and transfers it to the red photoelectronic device50R.

The intermediate insulation layer 65 is formed on the color filterlayers 70B and 70R. The intermediate insulation layer 65 eliminates astep caused by the color filter layers 70B and 70R and smoothes thesurface. The intermediate insulation layer 65 and the lower insulationlayer 60 may include a contact hole (not shown) exposing a pad, and atrench exposing the charge storage unit 55G of a green pixel.

The organic optoelectronic device 100 is formed on the intermediateinsulation layer 65. The organic photoelectronic device 100 mayselectively sense light in a green wavelength region.

The organic photoelectronic device 100 includes a lower electrode 10 andan upper electrode 20, and a green light absorption layer 30G interposedbetween the lower electrode 10 and the upper electrode 20. One of thelower electrode 10 and the upper electrode 20 is an anode and the otheris a cathode.

The lower electrode 10 and the upper electrode 20 may belight-transmitting electrodes, and the light-transmitting electrodes maybe made of, for example, a transparent conductor such as indium tinoxide (ITO) or indium zinc oxide (IZO), or may be metal thin layershaving a thin thickness of several nanometers or several tens ofnanometers or metal thin layers having a thin thickness of severalnanometers to several tens of nanometers doped with a metal oxide.

The green light absorption layer 30G selectively absorbs light in agreen wavelength region, and transmits light in other wavelength regionsbesides the green wavelength region, that is, light in a blue wavelengthregion and a red wavelength region.

The green light absorption layer 30G may include a p-type semiconductorand an n-type semiconductor, and the p-type semiconductor and the n-typesemiconductor may form a pn junction. At least one of the p-typesemiconductor and the n-type semiconductor may selectively absorb lightin a green wavelength region, and may selectively absorb light in agreen wavelength region to generate excitons, and then the generatedexcitons may be separated into holes and electrons to provide aphotoelectric effect. The green light absorption layer 30G may replace agreen filter.

Each of the p-type semiconductor and the n-type semiconductor may havean energy bandgap of, for example, about 2.0 eV to about 2.5 eV, and thep-type semiconductor and the n-type semiconductor may have a LUMOdifference of, for example, about 0.2 eV to about 0.7 eV.

The p-type semiconductor material may be, for example, quinacridone or aderivative thereof, or sub-phthalocyanine or a derivative thereof, andthe n-type semiconductor material may be, for example, a cyanovinylgroup-containing thiophene derivative, fullerene, or a fullerenederivative, but are not limited thereto.

The green light absorption layer 30G may be a single layer or amultilayer. The green light absorption layer 30G may be, for example, anintrinsic layer (I layer), a p-type layer/I layer, an I layer/n-typelayer, a p-type layer/I layer/n-type layer, a p-type layer/n-type layer,and the like.

The intrinsic layer (I layer) may include the p-type semiconductor andthe n-type semiconductor in a thickness ratio of about 1:100 to about100:1. The compounds may be included in a thickness ratio ranging fromabout 1:50 to about 50:1 within the range, specifically, about 1:10 toabout 10:1, and more specifically, about 1 to about 1. When the p-typeand n-type semiconductors have a composition ratio within the range, anexciton may be effectively produced, and a pn junction may beeffectively formed.

The p-type layer may include the p-type semiconductor, and the n-typelayer may include the n-type semiconductor.

The green light absorption layer 30G may have a thickness of about 1 nmto about 500 nm. Within the range, the green light absorption layer 30Gmay have a thickness of about 5 nm to about 300 nm. When the green lightabsorption layer 30G has a thickness within the range, the active layermay effectively absorb light, effectively separate holes from electrons,and deliver them, effectively improving photoelectric conversionefficiency.

The organic photoelectronic device 100 may produce excitons on theinside when light enters from the upper electrode 20 and the green lightabsorption layer 30G selectively absorbs light in a green wavelengthregion. Excitons are separated into holes and electrons in the greenlight absorption layer 30G, and the separated holes are moved to theanode side, which is one of the lower electrode 10 and the upperelectrode 20, and the separated electrons are moved to a cathode side,which is the other of the lower electrode 10 and the upper electrode 20,so as to allow a current to flow. The separated electrons or holes maybe collected in the charge storage unit 55G. The light in otherwavelength regions except the green wavelength region may be transmittedto the lower electrode 10 and the color filters 70B and 70R, and may besensed by the blue photoelectronic device 50B or the red photoelectronicdevice 50R.

The green light absorption layer 30G may be formed on the front side ofthe image sensor, and thus light may be absorbed at the front side andthe light area may be increased to have high light absorptionefficiency.

The blue photoelectronic device 50B, and the red photoelectronic device50R, integrated in the semiconductor substrate 110, and the organicphotoelectronic device 100 including the green light absorption layer30G, may provide the first photoelectronic device.

The upper insulation layer 80 is formed on the organic photoelectronicdevice 100.

The upper insulation layer 80 may be, for example, made of an inorganicinsulating material such as a silicon oxide and/or a silicon nitride, ora low dielectric constant (low K) material such as SiC, SiCOH, SiCO, andSiOF. The upper insulation layer 80 may be omitted.

The second photoelectronic device 90 is formed on the upper insulationlayer 80.

The second photoelectronic device 90 includes the lower electrode 91 andthe upper electrode 92 facing each other, and the infrared lightabsorption layer 93 interposed between the lower electrode 91 and theupper electrode 92.

One of the lower electrode 91 and the upper electrode 92 is an anode andthe other is a cathode. The lower electrode 91 and the upper electrode92 may be light-transmitting electrodes, and the light-transmittingelectrodes may be made of, for example, a transparent conductor such asindium tin oxide (ITO) or indium zinc oxide (IZO), or may be metal thinlayers having a thin thickness of several nanometers or several tens ofnanometers or metal thin layers having a thin thickness of severalnanometers to several tens of nanometers doped with a metal oxide.

The infrared light absorption layer 93 may include a materialselectively absorbing light in an infrared region. The infrared lightabsorption layer 93 may include a p-type and an n-type semiconductor,and at least one of the p-type semiconductor and the n-typesemiconductor may be a material selectively absorbing light in aninfrared region, for example a quinoid metal complex compound, a cyaninecompound, an immonium compound, a diimmonium compound, a triarylmethanecompound, a dipyrromethene compound, a diquinone compound, anaphthoquinone compound, an anthraquinone compound, a squaryliumcompound, a rylene compound, a phthalocyanine compound, anaphthalocyanine compound, a perylene compound, an anthraquinonecompound, a nickel-dithiol complex compound, a derivative thereof, or acombination thereof, but example embodiments are not limited thereto.

The infrared light absorption layer 93 may have a thickness of about 1nm to about 500 nm. Within the range, the infrared light absorptionlayer 93 may have a thickness of about 5 nm to about 300 nm. When theinfrared light absorption layer 93 has a thickness within the range, theinfrared light absorption layer 93 may effectively absorb light in aninfrared region, effectively separate holes from electrons, and deliverthem, effectively improving photoelectric conversion efficiency.

The second photoelectronic device 90 may produce excitons on the insidewhen light enters from the upper electrode 92, and the infrared lightabsorption layer 93 selectively absorbs light in the infrared raywavelength region. Excitons are separated into holes and electrons inthe infrared light absorption layer 93, and the separated holes aremoved to the anode side, which is one of the lower electrode 91 and theupper electrode 92, and the separated electrons are moved to the cathodeside, which is the other of the lower electrode 91 and the upperelectrode 92, so as to flow a current. The separated electrons or holesmay be collected in a charge storage unit (not shown).

The second photoelectronic device 90 selectively absorbs light in aninfrared region, and transmits light in other wavelength regions besidesthe infrared region.

A focusing lens (not shown) may be further formed on the secondphotoelectronic device 90. The focusing lens may control a direction ofincident light and gather the light in one region. The focusing lens mayhave a shape of, for example, a cylinder or a hemisphere, but exampleembodiments are not limited thereto.

In FIG. 2, the second photoelectronic device 90 is stacked on theorganic photoelectronic device 100, but example embodiments are notlimited thereto, and the organic photoelectronic device 100 may bestacked on the second photoelectronic device 90.

In FIG. 2, the blue photoelectronic device 50B and the redphotoelectronic device 50R are integrated in the semiconductor substrate110, and the organic photoelectronic device 100 includes the green lightabsorption layer 30G, but example embodiments are not limited thereto.That is, the blue photoelectronic device and the green photoelectronicdevice may be integrated in the semiconductor substrate 110 and theorganic photoelectronic device 100 may include a red light absorptionlayer, or the red photoelectronic device and the green photoelectronicdevice may be integrated in the semiconductor substrate 110 and theorganic photoelectronic device 100 may include a blue light absorptionlayer.

The image sensor according to the present example embodiments includesthe first photoelectronic device sensing light in a visible light regionand the second photoelectronic device sensing light in an infraredregion and that are stacked in a vertical direction, and therebyfeatures of the first photoelectronic device and the secondphotoelectronic device may be maintained without increasing an area ofthe image sensor. Particularly, sensitivity and luminance of the imagesensor may be prevented from abruptly decreasing under low illuminationenvironments of, for example, less than about 11 lux, and highsensitivity and high luminescence characteristics may be realized due tothe second photoelectronic device sensing light in an infrared region.

The image sensor according to the present example embodiments includes acolor filter layer adsorbing light in a blue wavelength region and lightin a red wavelength region as a first photoelectronic device, and agreen photoelectronic device absorbing light in a green wavelengthregion, which are stacked in a vertical direction, and thereby an areaof an image sensor may be decreased and down-sizing of an image sensormay be realized. The photoelectronic device selectively absorbing lightin a green wavelength region may be formed on a front side of an imagesensor, and increases an area absorbing light and ensures an area of acolor filter layer resulting in improvement of light absorptionefficiency.

FIG. 3 is a cross-sectional view of an image sensor according to furtherexample embodiments.

Referring to FIG. 3, an image sensor according to further exampleembodiments includes a semiconductor substrate 110 including a bluephotoelectronic device 50B and a red photoelectronic device 50R, a lowerinsulation layer 60, an organic photoelectronic device 100, an upperinsulation layer 80, and a second photoelectronic device 90, like theabove example embodiments.

The semiconductor substrate 110 may be a silicon substrate, and isintegrated with the blue photoelectronic device 50B, the redphotoelectronic device 50R, a charge storage unit 55G, and atransmission transistor (not shown). The blue photoelectronic device 50Band the red photoelectronic device 50R may be photodiodes.

However, the image sensor according to the present example embodimentsmay include the blue photoelectronic device 50B and the redphotoelectronic device 50R stacked in a vertical direction, unlike theabove example embodiments. The blue photoelectronic device 50B and thered photoelectronic device 50R are electrically connected to chargestorage units (not shown), and the information sensed by thephotoelectronic devices may be transferred by a respective transmissiontransistor. The blue photoelectronic device 50B and the redphotoelectronic device 50R may selectively absorb light in eachwavelength region depending on a stack depth.

A metal wire (not shown) and a pad (not shown) are formed on thesemiconductor substrate 110. In order to decrease signal delay, themetal wire and the pad may be made of a metal having low resistivity,for example, aluminum (Al), copper (Cu), silver (Ag), and alloysthereof, but example embodiments are not limited thereto. Further,example embodiments are not limited to the above-described structure,and the metal wire and pad may be positioned under the bluephotoelectronic device 50B and the red photoelectronic device 50R.

The lower insulation layer 60 is formed on the semiconductor substrate110. The lower insulation layer 60 may be made of an inorganicinsulating material such as a silicon oxide and/or a silicon nitride, ora low dielectric constant (low K) material such as SiC, SiCOH, SiCO, andSiOF.

The lower insulation layer 60 has a trench exposing the photoelectronicdevices 50B and 50R and the charge storage 55G of each pixel. The trenchmay be filled with fillers.

The organic photoelectronic device 100 is formed on the lower insulationlayer 60. The organic photoelectronic device 100 may selectively senselight in a green wavelength region.

The organic photoelectronic device 100 includes a lower electrode 10 andan upper electrode 20 facing each other, and a green light absorptionlayer 30G interposed between the lower electrode 10 and the upperelectrode 20. One of the lower electrode 10 and the upper electrode 20is an anode and the other is a cathode.

The lower electrode 10 and the upper electrode 20 may belight-transmitting electrodes, and the light-transmitting electrodes maybe made of, for example, a transparent conductor such as indium tinoxide (ITO) or indium zinc oxide (IZO), or may be metal thin layershaving a thin thickness of several nanometers or several tens ofnanometers or metal thin layers having a thin thickness of severalnanometers to several tens of nanometers doped with a metal oxide.

The green light absorption layer 30G selectively absorbs light in agreen wavelength region and transmits light in other wavelength regionsbesides the green wavelength region, that is a blue wavelength regionand a red wavelength region.

The green light absorption layer 30G may include, for example, a p-typesemiconductor and an n-type semiconductor, and the p-type semiconductorand the n-type semiconductor may form a pn junction. At least one of thep-type semiconductor and the n-type semiconductor may selectively absorblight in a green wavelength region, and may selectively absorb light ina green wavelength region to generate excitons, and then the generatedexcitons may be separated into holes and electrons to provide aphotoelectric effect. The green light absorption layer 30G may replace agreen filter.

The green light absorption layer 30G may be formed on the front side ofthe image sensor, and thus light may be absorbed at the front side andthe light area may be increased to have high light absorptionefficiency.

The organic photoelectronic device 100 including the bluephotoelectronic device 50B, the red photoelectronic device 50R, and thegreen light absorption layer 30G integrated in the semiconductorsubstrate 110 may provide the first photoelectronic device.

The upper insulation layer 80 is formed on the organic photoelectronicdevice 100.

The upper insulation layer 80 may be, for example, made of an inorganicinsulating material such as a silicon oxide and/or a silicon nitride, ora low dielectric constant (low K) material such as SiC, SiCOH, SiCO, andSiOF. The upper insulation layer 80 may be omitted.

The second photoelectronic device 90 is formed on the upper insulationlayer 80.

The second photoelectronic device 90 includes a lower electrode 91 andan upper electrode 92 facing each other, and an infrared lightabsorption layer 93 interposed between the lower electrode 91 and theupper electrode 92.

One of the lower electrode 91 and the upper electrode 92 is an anode andthe other is a cathode. The lower electrode 91 and the upper electrode92 may be light-transmitting electrodes, and the light-transmittingelectrodes may be made of, for example, a transparent conductor such asindium tin oxide (ITO) or indium zinc oxide (IZO), or may be metal thinlayers having a thin thickness of several nanometers or several tens ofnanometers or metal thin layers having a thin thickness of severalnanometers to several tens of nanometers doped with a metal oxide.

The infrared light absorption layer 93 may include a materialselectively absorbing light in an infrared region. The infrared lightabsorption layer 93 may include a p-type and n-type semiconductor, andat least one of the p-type semiconductor and the n-type semiconductormay be a material selectively absorbing light in an infrared region, forexample a quinoid metal complex compound, a cyanine compound, animmonium compound, a diimmonium compound, a triarylmethane compound, adipyrromethene compound, a diquinone compound, a naphthoquinonecompound, an anthraquinone compound, a squarylium compound, a rylenecompound, a phthalocyanine compound, a naphthalocyanine compound, aperylene compound, an anthraquinone compound, a nickel-dithiol complexcompound, a derivative thereof, or a combination thereof, but exampleembodiments are not limited thereto.

The infrared light absorption layer 93 may have a thickness of about 1nm to about 500 nm. Within the range, the infrared light absorptionlayer 93 may have a thickness of about 5 nm to about 300 nm. When theinfrared light absorption layer 93 has a thickness within the range, theinfrared light absorption layer 93 may effectively absorb light in aninfrared region, effectively separate holes from electrons, and allowthe separated holes and electrons to migrate, effectively improvingphotoelectric conversion efficiency.

The second photoelectronic device 90 selectively absorbs light in aninfrared region, and transmits light in other wavelength regions besidesthe infrared region.

A focusing lens (not shown) may be further formed on the secondphotoelectronic device 90. The focusing lens may control a direction ofincident light and gather the light in one region. The focusing lens mayhave a shape of, for example, a cylinder or a hemisphere, but exampleembodiments are not limited thereto.

In FIG. 3, the second photoelectronic device 90 is stacked on theorganic photoelectronic device 100 but example embodiments are notlimited thereto, and the organic photoelectronic device 100 may bestacked on the second photoelectronic device 90.

In FIG. 3, the blue photoelectronic device 50B and the redphotoelectronic device 50R are integrated in the semiconductor substrate110, and the organic photoelectronic device 100 includes the green lightabsorption layer 30G, but example embodiments are not limited thereto.The blue photoelectronic device and the green photoelectronic device maybe integrated in the semiconductor substrate 110 and the organicphotoelectronic device 100 may include a red light absorption layer.Herein, the green photoelectronic device may be positioned under theblue photoelectronic device. Likewise, the red photoelectronic deviceand the green photoelectronic device may be integrated in thesemiconductor substrate 110 in a vertical direction, and the organicphotoelectronic device 100 may include a blue light absorption layer.Herein, the red photoelectronic device may be positioned under the greenphotoelectronic device.

FIG. 4 is a cross-sectional view of an image sensor according to furtherexample embodiments.

Referring to FIG. 4, an image sensor according to further exampleembodiments includes a color filter 70 and the second photoelectronicdevice 90, positioned on a same surface of an organic photoelectronicdevice 100, without the color filter 70 being interposed between theorganic photoelectronic device 100 and second photoelectronic device 90.An upper insulator 80 may optionally be interposed between the colorfilter 70 and the organic photoelectronic device 100 and/or between thesecond photoelectronic device 90 and the organic photoelectronic device100.

The image sensor according to the present example embodiments includesthe first photoelectronic device sensing light in a visible lightregion, and the second photoelectronic device sensing light in aninfrared region and that are stacked in a vertical direction, andthereby features of the first photoelectronic device and the secondphotoelectronic device may be maintained without increasing an area ofthe image sensor. Particularly, sensitivity and luminance of the imagesensor may be prevented from abruptly decreasing under low illuminationenvironments of, for example, less than about 11 lux, and highsensitivity and high luminescence characteristics may be realized due tothe second photoelectronic device sensing light in an infrared region.

The image sensor according to the present example embodiments includes ared photoelectronic device and a blue photoelectronic device as well asan organic photoelectronic device selectively absorbing light in a greenwavelength region and has a stack structure in a vertical direction, andthereby an area of an image sensor may be decreased and down-sizing ofan image sensor may be realized. The photoelectronic device selectivelyabsorbing light in a green wavelength region may be formed on a frontside of an image sensor, and increases an area absorbing light andensures an area of a color filter layer resulting in improvement oflight absorption efficiency.

The image sensor according to the present example embodiments maysimplify a structure and a process by not including a color filterlayer.

The image sensor may be applied to various electronic devices, forexample a mobile phone, a digital camera, a biosensor, and the like, butexample embodiments are not limited thereto.

While this disclosure has been described in connection with what ispresently considered to be practical example embodiments, it is to beunderstood that the invention is not limited to the disclosedembodiments, but, on the contrary, is intended to cover variousmodifications and equivalent arrangements included within the spirit andscope of the appended claims.

<Description of symbols> 50B: blue photoelectronic device 50R: redphotoelectronic device 55G, 55I: charge storage 60: lower insulationlayer 65: intermediate insulation layer 70: color filter layer 80: upperinsulation layer 90: second photoelectronic device 10, 91: lowerelectrode 20, 92: upper electrode 30G: green light absorption layer 93:infrared light absorption layer 110: semiconductor substrate

What is claimed is:
 1. An image sensor, comprising: a firstphotoelectronic device including at least one of a blue photoelectronicdevice sensing light in a blue wavelength region, a red photoelectronicdevice sensing light in a red wavelength region, and a greenphotoelectronic device sensing light in a green wavelength region; and asecond photoelectronic device stacked on one side of the firstphotoelectronic device without being interposed by a color filter,wherein the second photoelectronic device senses light in an infraredregion, wherein the first photoelectronic device and the secondphotoelectronic device are stacked in a vertical direction, and thesecond photoelectronic device is positioned closer to a light incidenceside than the first photoelectronic device.
 2. The image sensor of claim1, wherein the blue wavelength region has a maximum absorptionwavelength (λmax) at greater than or equal to about 400 nm and less than500 nm, the red wavelength region has a maximum absorption wavelength(λmax) at greater than about 580 nm and less than or equal to about 700nm, the green wavelength region has a maximum absorption wavelength(λmax) at about 500 nm to about 580 nm, and the infrared region has amaximum absorption wavelength (λmax) at greater than about 700 nm. 3.The image sensor of claim 1, wherein the first photoelectronic deviceincludes the blue photoelectronic device, the red photoelectronicdevice, and the green photoelectronic device, and the bluephotoelectronic device, the red photoelectronic device, and the greenphotoelectronic device are integrated in a silicon substrate.
 4. Theimage sensor of claim 3, further comprising: a color filter layer on theone side of the first photoelectronic device or one side of the secondphotoelectronic device, wherein the color filter layer includes a bluefilter selectively absorbing light in a blue wavelength region, a redfilter selectively absorbing light in a red wavelength region, and agreen filter selectively absorbing light in a green wavelength region,and transmitting light in an infrared region.
 5. The image sensor ofclaim 4, wherein the color filter layer is at a side of the image sensoron which light is incident.
 6. The image sensor of claim 1, wherein thefirst photoelectronic device includes an organic photoelectronic device,the organic photoelectronic device includes (i) a pair oflight-transmitting electrodes facing each other, and (ii) a visiblelight absorption layer between the pair of light-transmittingelectrodes, and the visible light absorption layer selectively absorbslight in one of the blue wavelength region, the red wavelength region,and the green wavelength region.
 7. The image sensor of claim 6, whereinthe visible light absorption layer selectively absorbs light in a greenwavelength region.
 8. The image sensor of claim 7, further comprising: asilicon substrate on one side of the organic photoelectronic device,wherein the blue photoelectronic device and the red photoelectronicdevice are integrated in the silicon substrate.
 9. The image sensor ofclaim 8, wherein the blue photoelectronic device and the redphotoelectronic device are spaced apart from each other in a horizontaldirection.
 10. The image sensor of claim 9, further comprising: a colorfilter layer between the organic photoelectronic device and the siliconsubstrate, wherein the color filter layer includes a blue filterselectively absorbing light in a blue wavelength region and a red filterselectively absorbing light in a red wavelength region.
 11. The imagesensor of claim 8, wherein the blue photoelectronic device and the redphotoelectronic device are stacked in a vertical direction, and the redphotoelectronic device is positioned further from a surface of thesilicon substrate than the blue photoelectronic device.
 12. The imagesensor of claim 1, wherein the second photoelectronic device includes(i) a pair of light-transmitting electrodes facing each other; and (ii)an infrared light absorption layer between the pair oflight-transmitting electrodes, and the infrared light absorption layerselectively absorbs light in an infrared region.
 13. The image sensor ofclaim 12, wherein the infrared light absorption layer includes at leastone selected from a quinoid metal complex compound, a cyanine compound,an immonium compound, a diimmonium compound, a triarylmethane compound,a dipyrromethene compound, diquinone compound, a naphthoquinonecompound, an anthraquinone compound, a squarylium compound, a rylenecompound, a phthalocyanine compound, a naphthalocyanine compound, aperylene compound, an anthraquinone compound, a nickel-dithiol complexcompound, and a derivative thereof.
 14. The image sensor of claim 1,wherein the first photoelectronic device and the second photoelectronicdevice contact each other.
 15. The image sensor of claim 1, furthercomprising: a transparent insulator between the first photoelectronicdevice and the second photoelectronic device.
 16. An electronic device,comprising the image sensor according to claim
 1. 17. The electronicdevice of claim 16, wherein the electronic device is a mobile phone, adigital camera, or a bio-sensing camera.
 18. An image sensor,comprising: a first photoelectronic device including at least one of ablue photoelectronic device sensing light in a blue wavelength region, ared photoelectronic device sensing light in a red wavelength region, anda green photoelectronic device sensing light in a green wavelengthregion; and a second photoelectronic device stacked on one side of thefirst photoelectronic device without being interposed by a color filter,the second photoelectronic device sensing light in an infrared region,wherein the first photoelectronic device and the second photoelectronicdevice are stacked in a vertical direction, wherein the secondphotoelectronic device is closer to a light incidence side than thefirst photoelectronic device, and wherein the first photoelectronicdevice includes an organic photoelectronic device, the organicphotoelectronic device including (i) a pair of light-transmittingelectrodes facing each other, and (ii) a visible light absorption layerbetween the pair of light-transmitting electrodes, the visible lightabsorption layer selectively absorbing light in the green wavelengthregion having a maximum absorption wavelength (λmax) at about 500 nm toabout 580 nm.
 19. The image sensor of claim 18, further comprising: asilicon substrate on one side of the organic photoelectronic device,wherein the blue photoelectronic device and the red photoelectronicdevice are integrated in the silicon substrate.
 20. The image sensor ofclaim 19, wherein the blue photoelectronic device and the redphotoelectronic device are spaced apart from each other in a horizontaldirection.